Method of making a wheel end assembly with a machined rotor having reduced on-vehicle runout

ABSTRACT

The present invention involves a wheel end and a method of making a wheel end to be installed on a vehicle for reduced lateral runout. The method includes assembling a rotor and components with bearing surfaces to define an assembled module configured to be mounted to the vehicle and preloading the bearing surfaces of the assembled module. The method further includes mounting the assembled module on a holding fixture and rotating the assembled module on the holding fixture. The method further comprises machining a final cut on the rotor to a rotor width while rotating, after assembling and preloading the assembled module to define the wheel end of the vehicle. After machining, the wheel end remains assembled and preloaded when the assembled module is installed on the vehicle for reduced lateral runout.

BACKGROUND OF THE INVENTION

[0001] The present invention is related to wheel ends and a method ofmaking a wheel end to be installed on a vehicle for reduced runout ofthe vehicle.

[0002] Wheel ends and brake modules for motor vehicles are known andhave been widely used in the automotive industry for many years. Atypical wheel end of a vehicle generally includes a hub to which a halfshaft or stub shaft attaches for rotation about an axis. A bearingassembly is disposed on the hub and mounts within a body of a steeringknuckle to allow the half shaft, for example, to rotate and drive thehub about the axis. A rotor may be attached to the hub for rotationalmovement about the axis.

[0003] Although current wheel end designs are adequate, manufacturers ofwheel end components have been challenged on issues pertaining toon-vehicle runout and lateral runout of wheel ends. It is known that foreach interface or connection within a wheel end on a vehicle, apotential for on-vehicle runout or lateral runout of is possible duringvehicle use. In many situations, on-vehicle runout may range between 25micron and 100 micron. As a result, an operator or occupant of thevehicle may experience undesirable vibrations and unfamiliar movementsof the vehicle when braking or cornering of the vehicle during operationthereof. Many manufacturers of wheel end components have attempted toreduce such on-vehicle or lateral runout with results which may beimproved.

BRIEF SUMMARY OF THE INVENTION

[0004] Thus, it is one aspect of the present invention to provide animproved method of making a wheel end to be installed on a vehicle forreduced lateral runout.

[0005] It is another aspect of the present invention to provide a methodof making a wheel end wherein machining a final cut on a rotor of thewheel end is performed after assembling and preloading the module forinstallation on a vehicle.

[0006] Another aspect of the present invention includes a method ofmaking a wheel end wherein a preload is maintained while machining afinal cut on a rotor of the wheel end and up to installation thereof ona vehicle.

[0007] It is yet another aspect of the present invention to provide awheel end or brake module having a hub and a rotor attached thereto. Thehub includes a flange and a hub shaft having inboard and outboard ends.The flange extends from the hub shaft at the outboard end. The rotor ismounted to the flange for radial movement with the hub. The rotor ismachined after assembling and preloading the wheel end.

[0008] In one embodiment, a method of the present invention includesassembling the rotor and components with bearing surfaces to define anassembled module which is configured to be installed on the vehicle. Themethod further includes preloading the bearing surfaces, after the rotorand components are assembled, to define a preloaded condition of theassembled module. When assembled and preloaded, the assembled wheel endremains assembled and preloaded for installment on a vehicle. The methodfurther includes mounting the assembled wheel end on a holding fixtureand rotating the assembled wheel end about an axis on the holdingfixture.

[0009] Furthermore, the method includes machining a final cut on therotor to a rotor width while rotating, after assembling and preloadingthe assembled module to define the wheel end to be installed on thevehicle. Then, the wheel end remains assembled and preloaded forinstallment on a vehicle. It has been determined that machining thefinal cut on the rotor after assembling and preloading the moduleprovides a substantially reduced on-vehicle or lateral runout on thevehicle so long as the wheel end remains assembled and preloaded forinstallation. This provides a reduced lateral runout on the vehicle.

[0010] It has been determined that the wheel end provides substantialreduction to lateral runout, since after machining the wheel end remainsassembled and preloaded up to installation of the wheel end on thevehicle. This prevents and avoids additional interfaces and, in turn,additional runout to the wheel end after machining the final cut on therotor.

[0011] Further objects, features and advantages of the invention willbecome apparent from consideration of the following description and theappended claims when taken in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012]FIG. 1 is a perspective view of a wheel end having reduced lateralrunout in accordance with one embodiment of the present invention;

[0013]FIG. 2 is a cross-sectional view of the wheel end taken alonglines 22 in FIG. 1;

[0014]FIG. 3 is another side view of the wheel end depicting a flange ofa hub to which a rotor may be mounted;

[0015]FIG. 4 is an exploded view of the wheel end of FIG. 1 inaccordance with one embodiment of the present invention;

[0016]FIG. 5 is a side view of the wheel end depicting a rotor inaccordance with one embodiment of the present invention; and

[0017]FIG. 6 is a flow chart depicting one method of making the wheelend for reduced runout on a vehicle for reduced runout in accordancewith the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0018]FIG. 1 illustrates a wheel end 10 for a vehicle having reducedlateral runout in accordance with the present invention. As shown, thewheel end 10 generally includes a hub 13 and a hub pilot 13 b to which arotor 14 is mounted or affixed via bolts 47. Depicted in FIG. 2, abearing assembly 49 is disposed about the hub 13 and is received by asteering knuckle 17 which is mounted to the vehicle. As shown, a wheelend shaft or a mating shaft or a constant velocity joint housing andshaft housing and shaft 18 are disposed through the hub and rotor toallow the wheel end 10 to be driven.

[0019]FIG. 2 depicts a cross-sectional view of the wheel end 10 ofFIG. 1. As shown, wheel end 10 comprises hub 13 including a flange 16and a hub shaft 20 having inboard and outboard ends 22 and 23. Theflange 16 extends from the hub shaft 20 at the outboard end 23. The hubshaft 20 includes a stepped boss 24 formed radially thereon forreceiving races as described below. The hub shaft 20 further includes aninner wall 25 defining a receiving bore 26 formed therethrough. Theinner wall 25 has an internal spline 27 formed thereon. The receivingbore is configured to receive a mating shaft or constant velocity jointhousing and shaft housing and shaft 18 to define an axis A about whichthe hub 13 may rotate.

[0020] As shown in FIGS. 2-4, the flange 16 includes a face 28 having aplurality of mounting bores 30 formed therethrough for mounting a rotor14 on the face 28 of flange 16. The face 28 additionally has at leastone setting bore 31 formed therethrough and having internal threads. Asillustrated in FIG. 3, the face 28 of flange 16 includes inner portion32 and outer portion 34 which may be machined to a flange width orthickness as mentioned below. Face 28 further includes an annular groove36 formed radially thereon and in alignment with mounting bores 30. Thethickness between the inner and outer portions 32, 34 of the flange isgreater than the thickness of the flange at the annular groove 36.

[0021] The annular groove 36 allows compensation of potential volcanoingwhen a bolt 47 is inserted through mounting bore 30. Volcanoing asknown, is understood to be excess material and flash within wallsdefining the mounting bores displaced therethrough during assembly ofthe wheel end. The annular groove 36 provides a space or void in whichthe excess material may be received, preventing additional runout andother undesirable results. As shown in FIG. 3, the annular groove 36 isradially formed about the face 28 of flange 16 and is in alignment witheach of the mounting bores 30.

[0022]FIGS. 2 and 5 depict a rotor 14 including inboard hub mountingsurface 42 and outboard wheel mounting surface 43 and having a settingaperture 45 and a plurality of apertures 46 formed therethrough. Whenapertures 45 and 46 and bores 30 and 31 are in alignment, bolts 47 maybe disposed through bore 30 and aperture 46 and set screw 48 may bedisposed through bore 31 and aperture 45 to mount rotor 14 onto flange16.

[0023] Wheel end 10 further includes bearing assembly 49 radiallydisposed about hub shaft 20 on its outer surface 24. Bearing assembly 49is abutted by a stepped boss 29 at the outboard end 23 and by theconstant velocity joint housing and shaft 18 at the inboard end 22.Bearing assembly 49 includes inboard inner bearing race 50 and outboardinner bearing race 51 having inboard inner raceway 52 and outboard innerraceway 53, respectively, formed thereon. Bearing assembly 49 furtherincludes outer bearing race 56 having inboard outer raceway 57 andoutboard outer raceway 58. The bearing assembly 49 is configured suchthat inboard and outboard inner bearing races 50, 51 cooperate withouter bearing race 56. Thus, inboard and outboard inner bearing races50, 51 cooperate with outer bearing race 56 such that inboard innerraceway 52 is in alignment with inboard outer raceway 57 to housebearings 60 therein. Moreover, outboard inner raceway 53 is in alignmentwith outboard outer raceway 58 to house bearing 60 therein. As shown,inboard and outboard inner bearing races 50, 51 are radially disposedabout hub shaft 20 on stepped boss 24.

[0024]FIGS. 2 and 4 further illustrate a steering knuckle 17 having abody 73 and first and second knuckle arms 74, 75 extending from the body73. The first and second knuckle arms 74, 75 are mounted to a strut oran upper control arm and a low control arm, respectively, of the motorvehicle (not shown). As shown, steering knuckle 17 receives bearingassembly 49 mounted therein. The body 73 includes an inner wall 76formed therethrough to define a center bore 80 of the body.

[0025] As shown, the bearing assembly 49 is disposed in center bore 80and engages with inner wall 76 to be mounted therein. Constant velocityjoint housing and shaft housing and shaft 18 is disposed through thereceiving bore 26 of hub shaft 20 and through the center bore 80 ofsteering knuckle 17. In this embodiment, constant velocity joint housingand shaft housing and shaft 18 is a half shaft having a bell 90 and astem 92 extending therefrom. Stem 92 has an outer surface having anexternal spline 93 to be received in receiving bore 26. The inner wall25 of hub shaft 20 is configured to cooperate with the external spline93 of stem 92. This allows

[0026] torque to be transferred, as known, to provide rotation of rotor14 about axis A. The external spline is in mating relationship withinternal spline 27 of the hub 13, as known in the art.

[0027] The constant velocity joint housing and shaft housing and shaft18 is secured therein by locking nut 86 which locks onto a threadedportion at the end of the constant velocity joint housing and shafthousing and shaft. This allows the rotor and hub to be driven or rotatedabout axis A by the constant velocity joint housing and shaft 18. Inoperation, the constant velocity joint housing and shaft 18 is poweredby the vehicle to rotate or drive the rotor to which a wheel (not shown)may be mounted. Although the constant velocity joint housing and shaft18 is shown as a half shaft for a driven wheel end, a stub shaft fornon-driven wheel may be used without falling beyond the scope or spiritof the present invention.

[0028] It is understood that the wheel end depicted in FIGS. 1-5 anddiscussed above is merely one example of a wheel end which may bemachined in accordance with the present invention. Other designs andconfigurations of a wheel end may be used and do not fall beyond thescope or spirit of the present invention. For example, the hub shaft maybe configured to have one or a plurality of raceways integrally formedthereon thereby eliminating the need for one or a plurality of innerbearing races or bearing surfaces.

[0029]FIG. 6 illustrates a flow chart of one method 110 of making awheel end or brake module mentioned above to be installed on a vehiclefor reduced lateral runout. Method 110 includes assembling a rotor andcomponents with bearing surfaces to define an assembled wheel end orbrake module configured to be mounted to the vehicle in box 113. Thecomponents with bearing surfaces may include the knuckle, hub, bearingassembly, and constant velocity joint housing and shaft discussed above.As mentioned above, the rotor and corresponding components with bearingsurfaces are assembled to define the wheel end as shown in FIG. 1.

[0030] In box 116, the method 110 further includes preloading theassembled wheel end. This may be accomplished by tightening the constantvelocity joint housing and shaft 18 with the nut 86, and applying forceonto the bearing assembly to create a preload on the bearing assembly.In this embodiment, the step of preloading includes applying a setamount of radial load and thrust load on the components with bearingsurfaces for mounting the assembled module to the vehicle.

[0031] It is to be understood that the step of preloading the assembledwheel end includes applying a thrust load and/or a radial load to thebearing assembly as typically known. This may be accomplished byapplying an axial load on the wheel end shaft with the locking nut.However, other means of preloading may be used and do not fall beyondthe scope or spirit of the present invention. In this embodiment, thestep of preloading includes applying a set amount of radial load andthrust load, e.g. about 40,000 to 180,000 Newtons, on the componentswith bearing surfaces for mounting the assembled module to the vehicle.

[0032] Then, in box 120, the method further includes mounting theassembled wheel end on a holding fixture. In this embodiment, theholding fixture may be a multi-jaw chuck, e.g., a three-jaw chuck.However, the holding fixture may be any other fixture to which theassembled wheel is to be mounted, e.g., other multi-jaw chucks, avehicle, or a suspension sub-frame module of a vehicle. In thisembodiment, the constant velocity joint housing and shaft (mentionedabove) may be a half shaft for a driven wheel end. However, a stub shaftfor a non-driven wheel end may be implemented without falling beyond thescope or spirit of the present invention. The steering knuckle ismounted onto the holding fixture so that the components with bearingsurfaces and the rotor are rotatable about axis A.

[0033] Method 110 further includes rotating the assembled module aboutaxis A on the holding fixture in box 123. This allows the rotor to bedriven or rotated about axis A in preparation for machining a finalrotor cut. The method may further include measuring the actual runout ofthe assembled module when rotating about axis A.

[0034] Preferably, but not necessarily, the method 110 may includemachining a final hub cut on the face of the flange. The machiningapparatus may be configured to cut the inner and/or outer portions ofthe flange at a predetermined flange width. In this embodiment, theapparatus only cuts the inner and outer portions without contacting thesurface of the annular groove. It is to be noted that the flange widthmay be any desired width so long as the flange width is not less thanthe width of the walls defining the annular groove. It has beendetermined that the final hub cut provides a reduced runout on thevehicle so long as the preload is maintained up to installation of thewheel end on the vehicle.

[0035] Method 110 further includes machining a final rotor cut on therotor to a rotor width in box 126, while rotating, after assembling andpreloading the assembled module. To accomplish this, any suitablemachining apparatus or device may be used to machine the final rotor cuton the rotor to the rotor width. In this embodiment, machining the rotoris based on the measured or actual runout of the assembled module toreduce the measured runout therefrom. It has been determined thatmachining the rotor reduces runout to about 10 to 50 micron. In thisembodiment, the rotor width may be about 10-100 millimeters. The finalrotor cut represents a last cut performed on the rotor prior toinstallation of the wheel end to the vehicle. In this embodiment, therotor width may be reduced by 200-1,200 microns.

[0036] It has been determined that machining the final rotor cut on therotor after assembling the module and preloading the module provides awheel end having a substantially reduced runout on the vehicle. It hasbeen further determined that the result is a substantial reduced runoutrelative to other wheel ends. After machining the final cut on therotor, the wheel end is maintained in its assembled and preloadedcondition in box 130. Thus, the wheel end is to be installed on thevehicle without any disassembling or further unloading or preloading. Asa result, a runout of about 10-50 micron after machining the final cuton the rotor remains constant when the wheel end is installed on thevehicle. This avoids added runout to the wheel end and additionalmachining caused by further disassembling and unloading after the finalcut.

[0037] As a person skilled in the art will recognize from the previousdetailed description and from the figures and claims, modifications andchanges can be made to the preferred embodiments of the inventionwithout departing from the scope of this invention defined in thefollowing claims.

1. A method of making a wheel end to be installed on a vehicle forreduced lateral runout, the method comprising: assembling a rotor andcomponents with bearing surfaces to define an assembled moduleconfigured to be mounted to the vehicle; preloading the components withbearing surfaces of the assembled module to define a preloaded conditionof the assembled module; mounting the assembled module on a holdingfixture; rotating the assembled module on the holding fixture; machininga final cut on the rotor to a rotor width, while rotating, to define thewheel end of the vehicle; and maintaining the wheel end in the preloadedcondition before installing the wheel end on the vehicle.
 2. The methodof claim 1 further comprising measuring runout of the assembled modulebefore machining.
 3. The method of claim 2 wherein machining the rotoris based on the measured runout of the assembled module to reduce themeasured runout therefrom.
 4. The method of claim 2 wherein machiningthe rotor reduces runout to about 10-50 micron.
 5. The method of claim 1wherein the rotor width is about 10-100 millimeters.
 6. The method ofclaim 1 wherein the holding fixture is a multi-jaw chuck to which theassembled module is mounted.
 7. The method of claim 1 wherein thebearing surfaces include an inner bearing race having an inner racewayformed thereon and an outer bearing race having an outer raceway formedthereon, the outer bearing race cooperating with the inner bearing raceto house bearings within the inner and outer raceways.
 8. The method ofclaim 7 wherein the components include: a steering knuckle including abody having an inner wall formed therethrough to define a center bore ofthe body, the inner wall configured to receive the outer bearing race; ahub including a flange and a hub shaft having inboard and outboard ends,the flange extending from the hub shaft at the outboard end, the hubshaft being disposed in the center bore of the knuckle, the innerbearing race being disposed about the hub shaft to cooperate with theouter bearing race, the inner raceway being configured to cooperate withthe outer raceway to house bearings, the hub shaft having a receivingbore formed therethrough; a wheel end shaft disposed in the receivingbore of the hub shaft for rotational movement of the assembled module.9. The method of claim 8 wherein the wheel end shaft includes asimulated constant velocity joint, an actual constant velocity joint, ahalf shaft, and a stub shaft.
 10. The method of claim 1 wherein rotatingthe assembled module includes driving the assembled module on theholding fixture about an axis for machining the rotor.
 11. The method ofclaim 1 wherein the final cut on the rotor represents a last cutperformed on the rotor prior to installation of the wheel end on thevehicle.
 12. The method of claim 1 wherein preloading includes applyinga set amount of radial load and thrust load on the bearing surfaces formounting the assembled module on the vehicle.
 13. A method of making awheel end to be installed on a vehicle for reduced lateral runout, themethod comprising: assembling a rotor, a hub, and components withbearing surfaces to define an assembled module configured to be mountedto the vehicle; preloading the components with bearing surfaces of theassembled module to be mounted to the vehicle by applying a set amountof radial load and thrust load on the bearing surfaces to define apreloaded condition of the assembled module; mounting the assembledmodule on a fixture; rotating the assembled module on the fixture;machining a final cut on the rotor to a rotor width, while rotating theassembled module, after assembling and preloading the assembled module,to define the wheel end; and maintaining the wheel end in the preloadedcondition before installing the wheel end on the vehicle.
 14. The methodof claim 13 further comprising measuring runout of the vehicle based onthe assembled module before machining.
 15. The method of claim 14wherein machining the rotor is based on the measured runout of theassembled module to reduce the measured runout.
 16. The method of claim14 wherein machining the rotor reduces runout to about 10-50 micron. 17.The method of claim 13 wherein the rotor width is about 10-100millimeters.
 18. The method of claim 13 wherein the holding fixture is amulti-jaw chuck.
 19. The method of claim 13 wherein the bearing surfacesinclude an inner bearing race having an inner raceway formed thereon andan outer bearing race having an outer raceway formed thereon, the outerbearing race cooperating with the inner bearing race to house bearingswithin the inner and outer raceways.
 20. The method of claim 19 whereinthe components include: a steering knuckle including a body having aninner wall formed therethrough to define a center bore of the body, theinner wall configured to receive the outer bearing race; and a wheel endshaft disposed in the receiving bore of the hub shaft for rotationalmovement of the assembled module, wherein the hub including a flange anda hub shaft having inboard and outboard ends, the flange extending fromthe hub shaft at the outboard end, the hub shaft being disposed in thecenter bore of the knuckle, the inner bearing race being disposed aboutthe hub shaft to cooperate with the outer bearing race, the innerraceway being configured to cooperate with the outer raceway to housebearings, the hub shaft having a receiving bore formed therethrough. 21.The method of claim 20 further comprising attaching the rotor to theflange of the hub.
 22. The method of claim 20 wherein the constantvelocity joint housing and shaft is a simulated constant velocity jointhousing and shaft.
 23. The method of claim 13 wherein the final cut onthe rotor represents a last cut performed on the rotor prior toinstallation of the wheel end on the vehicle.
 24. The method of claim 13wherein preloading includes applying a set amount of radial load andthrust load on the bearing surfaces for mounting the assembled module onthe vehicle.
 25. The method of claim 13 wherein rotating the assembledmodule includes driving the assembled module on the holding fixtureabout an axis for machining the rotor.
 26. A method of making a wheelend to be installed on a vehicle for reduced lateral runout, the methodcomprising: assembling a hub and components with bearing surfaces todefine an assembled module configured to be mounted to the vehicle;preloading the components with bearing surfaces of the assembled moduleto define a preloaded condition of the assembled module; mounting theassembled module on a holding fixture; rotating the assembled module onthe holding fixture; machining a final hub cut on the hub to a hubwidth, while rotating; affixing the rotor to the hub of the assembledmodule on the holding fixture; rotating the assembled wheel end on theholding fixture; machining a final rotor cut on the rotor to a rotorwidth, while rotating; and maintaining the wheel end in the preloadedcondition before installing the wheel end on the vehicle.
 27. The methodof claim 26 wherein the holding fixture includes the vehicle, amulti-jaw chuck, a suspension sub-frame module.
 28. The method of claim1 wherein the holding fixture includes the vehicle, a multi-jaw chuck, asuspension sub-frame module.
 29. The method of claim 13 wherein theholding fixture includes the vehicle, a multi-jaw chuck, a suspensionsub-frame module.